Neutral gold and nickel bis[1-(pyridin-4-yl)-ethylene-1,2-dithiolene] complexes: Synthesis, structure and physical properties

The Ni and Au bis(dithiolene) complexes based on the 1-(pyridine-4-yl)-ethylene-1,2-dithiolate ligand were prepared in their neutral state and characterized namely by single-crystal X-ray diffraction, electronic UV–Vis–NIR spectroscopy, EPR and magnetic susceptibility measurements. The crystal structure of the neutral complex [Ni(4-pedt)2]0 lacks a regular and multidimensional extended network of short contacts and as a consequence electrical conductivity measurements in single crystals show a semiconducting behavior with room temperature values of the order of 10−6 S/cm, while the magnetic measurements of the gold compounds indicate a reduced effective magnetic moment due to strong antiferromagnetic interactions between radical neutral complex units. The nitrogen coordination ability of theses complexes was demonstrated by the coordination of pyridine to a sodium ion observed in the [Au(4-pedt)2]2NaPF6 complex which was also characterized by single-crystal X-ray diffraction and magnetization. In this compound the Na ions in half occupied positions are coordinated by anion fluorine atoms and nitrogen and carbon atoms from the neutral [Au(4-pedt)2] complexes.

Graphical abstractThe synthesis of neutral [M(4-pedt)2] (M = Ni, Au) and [Au(4-pedt)2]2NaPF6 are described and these compounds are characterized by single-crystal X-ray diffraction electronic UV–Vis–NIR spectroscopy, EPR and magnetic susceptibility measurements.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Pyridine substituted bis(dithiolene) complexes. ► Neutral nickel and gold bis(dithiolene) complexes. ► Sodium side coordination by pyridine substituted neutral bis(dithiolene) complexes.